DAS Mistakes to Avoid: Design, Deployment, and Vendor Selection

Frequency Mismatch in RF Components

Each RF component operates within a specific frequency range. Using components outside their designated ranges can degrade signal quality or lead to total system failure. Therefore, it is important always to ensure that all components are compatible with the system’s frequency requirements.

Ignoring Power Handling Capacities

RF components near the power source are particularly vulnerable to overheating, which can reduce system reliability. It is critical to select components that can handle the anticipated power levels to prevent performance degradation.

Inaccurate Wall and Prediction Height Settings

• Wall Height: Modern RF simulation tools use accurate wall height inputs to predict coverage. Errors in this parameter can lead to costly redesigns and inadequate coverage.
• Prediction Height: In venues like warehouses with devices at varying heights, simulating coverage at multiple heights is essential to ensure consistent signal strength.

Over-Sectorization in Vertical Voids

Vertical voids, such as atriums, can create signal interference if multiple sectors overlap. Assigning a single sector to vertical voids or minimizing overlap between sectors to avoid this.

Neglecting Scalability

Failing to design for future expansion can lead to costly retrofits. Venues like stadiums and shopping malls should plan for sector splits to handle increased traffic as demand grows.

Poor Handover Demarcation

Placing handover points in high-traffic areas can result in dropped calls and degraded user experience – position handover demarcations in less congested areas to improve network stability.

Inaccessible Component Placement

Designs that place RF components in hard-to-reach areas complicate maintenance. Accessible placement of splitters, amplifiers, and cables can save time and reduce costs in the long term.

Over-Sectorization of Elevators

Elevator shafts in high-rise buildings often lead to frequent handovers, increasing the risk of call drops. Designing a single sector for the entire elevator shaft minimizes these issues.

Skipping Proper Needs Assessment

Every building has unique requirements based on layout, materials, and user traffic. Skipping a thorough assessment can lead to coverage gaps and poor system performance. Benchmark testing and iBwave designs are essential to ensure a tailored solution.

Overlooking Code Compliance

Public safety DAS must comply with stringent codes, such as NFPA 1225 and IFC standards. Non-compliance can lead to costly retrofits, delays in occupancy permits, and legal liabilities. To ensure compliance from the outset, work closely with the authority having jurisdiction (AHJ).

Failing to Address Pathway Survivability

Pathway survivability ensures that DAS cabling remains operational during emergencies, such as fires. This often requires using fire-rated cables or installing them in metal conduits. Neglecting this step can render the system non-compliant.

Neglecting System Monitoring

Modern DAS solutions require 24/7 monitoring to ensure performance and detect issues promptly. Failing to implement robust monitoring systems can result in prolonged downtime and compromised safety.

Poorly Executed Integration

Seamless integration with existing infrastructure and carrier networks is critical. A lack of coordination with carriers like AT&T, Verizon, or T-Mobile can result in a non-functional or “dark DAS,” requiring costly revisions.

Underestimating Deployment Complexity

Deploying DAS in large or complex buildings requires meticulous planning and coordination. Missteps in scheduling, resource allocation, or stakeholder communication can lead to delays and increased costs.

Common Vendor Selection Mistakes

• Choosing the Lowest Bid: Opting for the cheapest vendor may seem cost-effective but often results in hidden expenses due to inferior materials, inexperienced teams, and incomplete solutions. A low-cost DAS that fails to meet carrier standards can lead to costly rework.
• Not Vetting Vendor Expertise: Experience matters. A vendor without a proven track record, strong carrier relationships, or knowledge of complex code requirements may struggle to deliver a fully functional system.
• Ignoring Scalability: A short-sighted design can be expensive to upgrade. Your vendor should plan for future technology needs like 5G, Wi-Fi 6, or Private LTE.
• Neglecting Support and Maintenance: DAS systems require ongoing monitoring, maintenance, and support to prevent downtime. Ensure your vendor offers comprehensive post-installation services.
• Overlooking Carrier Relationships: Integration with wireless carriers is critical for system approval and functionality. Vendors without strong carrier ties may face challenges in obtaining necessary approvals.

Best Practices for Vendor Selection

• Engage Experts Early: Collaborate with experienced RF engineers and DAS integrators during the planning phase to anticipate potential challenges.
• Invest in Quality Components: High-quality components provide better performance, longevity, and compliance with evolving industry standards.
• Prioritize Code Compliance: Work closely with AHJs (Authorities Having Jurisdiction) and choose a vendor well-versed in local, state, and federal regulations.
• Plan for Future Needs: Ensure your DAS is designed to support future wireless advancements and evolving capacity demands.
• Conduct Thorough Testing: Proper system verification, including benchmark testing and two-radio tests, ensures performance and compliance.
• Select a Vendor with Proven Expertise: Choose a vendor with a solid reputation, extensive experience, and established relationships with wireless carriers to avoid costly missteps.